Mounting boxes and picks for coal-cutting machines



Aug. 23, 1966 A. SNIPE 3,268,260

MOUNTING BOXES AND PICKS FOR COAL-CUTTING MACHINES Filed March 7, 1963 2 Sheets-Sheet l /.9 l4/5/lA/574 lnvenlor MW W W4 /4 Wyn A Horneys Aug. 23, 1966 A. SNIPE 3,268,260

MOUNTING BOXES AND PICKS FOR COALCUTTING MACHINES Filed March 7, 1963 2 Sheets-Sheet 2 I nvenlor m M Mud a Attorneys United States Patent 3,268,260 MOUNTING BOXES AND PICKS FGR COAL-CUTTING MACHINES Arthur Snipe, Doncaster, England, assignor to Mining Supplies Limited Filed Mar. 7, 1963, Ser. No. 263,488 Claims priority application Great Britain, Mar. 24, 1962,

2 Claims. (Cl. 299-91) This invention relates to the picks and pick-mounting boxes of mining machines as used in cutting coal by the long wall method, and particularly to the type of machine having a rotary cutting head, provided with the pickmounting boxes, with its axis horizontal and projecting laterally from the machine perpendicularly to the working face, for the purpose of breaking out the material being mined to a depth substantially equal to the axial length of the head and to a height substantially equal to the overall diameter of the head and the picks mounted in it. The machine progresses parallel to the face from a gate-end previously cut to permit entry of the head by the required working depth, it being usual to mount such a machine over a conveyor laid parallel and close to the face to receive coal broken out by the cutting head.

The invention is particularly concerned with the mounting of point-attack picks in the cutting head of such a machine, the shanks of such picks being in line with the forwardly protruding body ending in the tip by which the actual attack is made on the coal. The invention consists in a construction of pick and a corresponding construction of mounting box such that any such pick can be combined with any such box to provide for the mounting of the pick in very simple and effective manner.

According to the present invention, a pick-mounting box and a point-attack pick for use in combination with each other in a coal-cutting machine comprise a solid block to provide the box, the block having a lengthwise cylindrical bore, with the forward end of the bore flared, and also having two transverse holes extending in divergent directions from one side intermediately of the length of the bore and breaking through opposite sides of the wall of the bore, together with a U-shaped stiff wire locking member to be driven with its two limbs in the respective holes, and pick with a cylindrical shank to be received in the bore of the box and with a body forming at its junction with the shank a shoulder to fit the flared end of the bore, the shank being grooved intermediately in its length at a distance from the shoulder corresponding to the distance of the holes from the flared end of the bore, for the reception at opposite sides of the shank of the limbs of the locking member when the limbs are driven into the holes to protrude into the bore at opposite sides.

Upon driving of the locking member into a box into which a pick shank has been inserted, each limb of the member moves along one of the holes, enters the groove at its side of the shank, and then continues along the remainder of the hole. Because the holes diverge, the limbs are forced to spread from an initial position in which their free ends have the same spacing as the inlet ends of the holes, and the spreading of the limbs resists removal of the member. The simple driving of the locking member into the holes thus serves to lock the pick to the box and to secure the locking member itself in the box.

Preferably, the two holes in the box are located towards the rear end of the groove location of an inserted shank, so that the insertion of the limbs of the locking member causes the shoulder of the pick to be drawn tightly to the flared end of the bore of the box.

The shoulder may be simply oblique, to fit a flared end of corresponding angle in the bore; but of course other shapes may be used, e.g., part-spherical, for the shoulder and the flare.

The cylindrical shank of the pick need have no more than a fairly close fit in the bore in the box, so that insertion and removal of the shank is simple. For the shank to be removed, the locking member must first be removed from the two holes, as by the insertion of the toe of a pinch bar into the base of the member to apply a powerful extracting leverage. It is desirable that that base shall not be exposed to wear or fracture, such as could lead to separation of its limbs and to their accidental release. The block may therefore be notched, with the inlets of the holes lying at the bottom of the notch, so that the base of the fully driven member lies below the surface of the block. With one side of the notch sharply inclined, access is provided for the insertion of the toe of the pinch bar.

The invention will now be further described with reference to preferred embodiments of pick-mounting box and pick shown by way of example in the accompanying drawings, in which:

FIGURE 1 is a side elevation of a pick secured in a box, with a part of the box broken away;

FIGURE 2 is a plan of the pick and box of FIGURE 1;

FIGURE 3 is a section of the box and pick shank taken on the line IIIIII of FIGURE 1; with a wire locking member (not in section) shown in inserted position;

FIGURE 4 is a section taken on the line IVIV of FIGURE 3;

FIGURE 5 is a side View of a wire locking member;

FIGURE 6 is a view of the pick alone, as viewed in FIGURE 1;

FIGURE 7 is a view, to a larger scale, of the pick tip as viewed in FIGURES 1 and 6;

FIGURE 8 shows the same tip, but as viewed in FIG- URE 2, as mounted in the lid of the pick;

FIGURE 9 shows the tip as seen from the right of FIGURE 8;

FIGURE 10 is a side elevation of one-half of a coalcutter head showing boxes and picks mounted round an end disc of the head and also round a helix of the head; and

FIGURE 11 is an end elevation of part of the head of FIGURE 10 as seen from the left.

FIGURES 1 to 4 show the mounting box 1 to be formed of a generally rectangular solid section block with a convex upper face 2. It has a lengthwise cylindrical bore 3, flared at 45 at its forward end 4. A point-attack pick 5 (FIGURE 6) has a tapering body 6 co-axial with a cylindrical shank 7, enlarging at its junction with the body 6 by a 45 oblique shoulder 8. The shank 7 is slightly shorter than the bore 3 of the box 1, and is tapered towards its end 9 to facilitate insertion in the bore. The shank 7 does not depend on any tapered fit with the bore 3 (the bore indeed being cylindrical), nor on any tight fit in the bore, but on the shoulder 8 being drawn tightly to the flare 4 and on the generally close fit in the bore inwardly from the flare 4.

The shoulder 8 is drawn to the flare 4 by the application of a U-shaped locking member or staple 10 (FIG- URE 5), consisting of stiff Wire initially having its two limbs 11 extending parallel from the base 12. The two limbs 11 are intended to serve as cotters, to be guided in the box 1 so as to protrude from opposite sides of the bore 3 into engagement with the shank 7 of the pick 5. To provide for this engagement, the shank 7-is grooved, most conveniently as a circumferential groove 13, which can be turned when the pick itself is being turned in a lathe. As shown by FIGURE 6 in particular, the groove 13 is wider than the diameter of the wire of the staple 10 and the bottom of the groove is radiused into its two end edges, so that the greatest depth of the groove (slightly more than one-half of the diameter of the wire) is away from its ends.

At a position towards the rear edge 14 (FIGURE 1) of the groove 13 two holes 15 extend transversely of the length of the box 1 from the bottom of a notch 16 across its convex top surface 2, these holes being slightly larger than the wire of the staple 10. At the bottom of the notch 16, the holes 15 have the spacing of the initially parallel limbs 11 of the staple, but the holes diverge through the box 1, for each to emerge at 17 (FIGURES 1 and 3) in one of two side notches 18. In following their divergent paths, the holes 15 are exposed over onehalf of their diameter at opposite sides of the bore 3 of the box 1, and then leave the bore, to continue at full diameter to their ends 17.

By hammering the base 12 of the staple 10, the limbs 11 are forced to follow the diverging holes 15 and therefore to assume the spread positions 11A (FIGURE 3), with about one-half of their diameter projecting into the bore 3, and therefore into the groove 13, where the holes intersect the bore. Because the base 12 finally enters the notch 16, there is a limit to which it can be hammered, so that the base cannot be subjected to excessive stress in bringing the limbs 11 to fully-insertion position, i.e., approximately emerging at the notches 18.

Because the holes 15 lie towards the rear edge 14 of the groove 13 (FIGURE 4), the limbs 11A of the staple 10 press on that rear edge 14 to draw the shank 7 of the pick along the bore 3, so that the shoulder 8 is drawn tightly to the flare 4, when the body 6 of the pick projects rigidly from the box 1 in co-axial alignment with the bore 3.

The limbs 11A having been spread apart, the staple 10 holds itself in the box 1; and the location of its base 12 in the notch 16 gives protection against wearing of the wire at that base. Nevertheless, the staple 10 can be readily removed, by the insertion of a pinch bar (not shown) along a lengthwise notch 19 in the top surface 2 of the box 1 and under the base 12. This frees the shank 7, so that the pick can be withdrawn from the box. If the pick tends to stick in the box, the pinch bar can be inserted in a notch 20 (FIGURES 1 and 2) in the forward end of the box, to apply releasing pressure to the shoulder 8.

The tapered body 6 of the pick 5 is provided with a hard metal, e.g., tungsten carbide, tip 21 (see particularly FIGURES 7 to 9), co-axi'ally mounted by having a conical base 22 brazed into a conical recess 23 leading to a pilot hole 25 to ensure accurate bedding of the base 22. The operative end 24 is here shown as pyramidal, but it could have other forms, e.g., conical. Although the tip 21 is shown as having the same diameter as the end of the tapered body 6, it could also be of somewhat greater diameter.

The mounting boxes 1 can be welded to form integral parts of a coal-cutting machine head, so that the locking of the picks 5 into the boxes by the staples secures the picks accurately and rigidly in the head, with each pick 5 directed in accordance with the position in which its box 1 is welded to the head. Thus, as shown at the left-hand side of FIGURE 10 and in FIGURE 11, each box 1 may be located in a notch 26 in the outer end of one of a series of thick plates 27 extending from a hub 28,

the plates 27 overlapping each other to form a helix. The rear end of each box 1 bears on a supporting shoulder 29 formed by the front edge of the next overlapping plate 27. Welded in its notch 26 and to the shoulder 29, each box 1 becomes an integral part of the plate assembly, to apply cutting thrust directly to the pick 5 projecting from the front of the box. The locking staples 10 lie protected in the notches 16, well inside the line of operation of the tips 21 of the picks.

At the left-hand side of FIGURE 10, the picks 5 are seen extending in the planes of the plates 27 to which their boxes 1 are secured. However, as shown at the right-hand side of FIGURE 10, the boxes 1 may be secured in inclined position, as to the end disc 30 of the head, to direct the picks 5 to one side or the other of the disc 30, as well as in the plane of that plate. There is also shown at 31 a shearer type pick, of which a number may be interspersed round the disc 30 with the pointattack picks 5.

What I claim is:

1. The combination of a point-attack mining machine pick having a cylindrical shank with a circumferential groove intermediately of its length and a tipped body larger in diameter than the'shank and joined to the shank by a shoulder portion of progressively increasing diameter and a mounting box which comprises a block in which is formed a longitudinal bore for the reception of the pick shank, one end of said bore being formed with a flared portion to fit the shoulder portion of the pick'to effect transmission of the working thrust between the block and the pick, said block having a pair of transversely extending holes, each of said holes extending in said block on both sides of said bore, said holes being continuously divergent from each other and positioned so as to intersect said bore on opposite sides thereof, and a generally U-shaped stitf wire locking member having limbs adapted to be received by said transverse holes so as to assume a divergent position for self locking in said block, an intermediate portion of each of said limbs serving to engage the rear edge of said groove in said shank to insure that said shoulder portion is drawn to and securely held against said flared portion.

2. The combination of claim 1 wherein is further provided a notch formed in said block adjacent the entrance to said holes so that a tool may be utilized to engage the base of said U-shaped member for removal.

References Cited by the Examiner UNITED STATES PATENTS 1,475,136 11/1923 Olson 27997 X 1,922,400 8/ 1933 Scott 28752.08 X 1,969,798 8/ 1934 Hultquist 27997 X 2,701,126 2/1955 McClennan 175-413 X 2,844,378 7/ 1958 Whistler et al 27997 2,933,295 4/1960 Rollins 29991 3,063,691 11/1962 Osgood 29992 3,074,703 1/1963 Adams et al. 299 3,093,366 6/1963 Proctor 299-92 3,148,741 9/1964 Holsing 4l3 ERNEST R. PURSER, Primary Examiner.

BENJAMIN HERSH, CHARLES E. OCONNELL,

Examiners. 

1. THE COMBINATION OF A POINT-ATTACK MINING MACHINE PICK HAVING A CYLINDRICAL SHANK WITH A CIRCUMFERENTIAL GROOVE INTERMEDIATELY OF ITS LENGTH AND A TIPPED BODY LARGER IN DIAMETER THAN THE SHANK AND JOINED TO THE SHANK BY A SHOULDER PORTION OF PROGRESSIVELY INCREASING DIAMETER AND A MOUNTING BOX WHICH COMPRISES A BLOCK IN WHICH IS FORMED A LONGITUDINAL BORE FOR THE RECEPTION OF THE PICK SHANK, ONE END OF SAID BORE BEING FORMED WITH A FLARED PORTION TO FIT THE SHOULDER PORTION OF THE PICK TO EFFECT TRANSMISSION OF THE WORKING THRUST BETWEEN THE BLOCK AND THE PICK, SAID BLOCK HAVING A PAIR OF TRANSVERSELY EXTENDING HOLES, EACH OF SAID HOLES EXTENDING IN SAID BLOCK ON BOTH SIDES OF SAID BORE, SAID HOLES BEING CONTINUOUSLY DIVERGENT FROM EACH OTHER AND POSITIONED SO AS TO INTERSECT SAID BORE ON OPPOSITE SIDES THEREOF, AND A GENERALLY U-SHAPED STIFF WIRE LOCKING MEMBER HAVING LIMBS ADAPTED TO BE RECEIVED BY SAID TRANSVERSE HOLES TO AS TO ASSUME A DIVERGENT POSITION FOR SELF LOCKING IN SAID BLOCK, AN INTERMEDIATE PORTION OF EACH OF SAID LIMBS SERVING TO ENGAGE THE REAR EDGE OF SAID GROOVE IN SAID SHANK TO INSURE THAT SAID SHOULDER PORTION IS DRAWN TO ANE SECURELY HELD AGAINST SAID FLARED PORTION. 